SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd538c0b3d0cf90c8d2308aecacb1d86e833d4c577da5be899631099423f17ed6' 
  AND token = 'Ji7JlFXPxTdRJkI74z5IoUDbg/zwPBf3gQL8sQpv94o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}